Where do you find parts for a McCULLOCH ms1838av chainsaw?

Short question, long answer. The IPL (Illustrated Parts List) number I am using to ID parts for that model (which is also known as a CS38EM) is McCulloch part number 211318-03. Any chainsaw parts house that has experience with Mac in the past should be able to chase parts for these. Some are available through MTD dealers (as Mac is now owned by MTD), and some you have to order through parts houses that specialize in obsolete parts. Some numbers that will hopefully help you: Mac Service Center: 800.5218559, Discount Marine: 906.466.2180, Original Equipment: 800.645.2031, and Bob's Lawn Mower: 607.638.9297. Don't underestimate your local lawn & garden shop, though. If they have access to MTD parts (and most all shops do), they will have access to a surprising amount of parts. You will pay less for parts this way, typically, than you will if you have to order them through a specialty obsolete parts house. You will be best served to find the IPL on the internet and figure out the part numbers yourself, as most parts guys don't want to go to the effort on hard-to-find IPLs for old saw models, especially for lower-dollar sales. If I can help further with this, you can email Matt at cnbyrent@canby.com. I have 15+ years in chasing parts, and am pretty successful finding most anything for lawn & garden. Good luck!